Skip to main content

Full text of "Text Book Of Mechanical Engineering"

See other formats



some parts of a pattern by lifting portions of sand on
' drawbacks} An example often quoted, and a very goo
purposes of explanation, is that of a lathe bed.

Fig. 62a shews a section of the pattern lying in th
The bed is reversed, so that the planed surfaces shall be


scum; and these surfaces are in the pattern made loose piei
The upper portion of the pattern can be easily removed, fc
problem is to withdraw the pieces a a. This can only be ac
by building the sand at b b on plates cc^ provided with hand
which they and the sand upon them may be removed, afl